The goal of this proposal is to upgrade the x-ray diffraction equipment in use in the Molecular Biophysics Department of The Medical Foundation of Buffalo. This equipment is shared.by a major user group of seven PHS funded and two non-PHS funded principal investigators, all members of the Molecular Biophysics Department. In total 16 professional crystallographers work on the projects involved. Upgrades for which funds are requested will provide us with a state-of-the-art facility consisting of three diffractometers, each fully equipped with accessories required for research efforts for which the instruments are designated, one rotating anode generator with cameras for protein data collection and two sealed tube generators equipped with four cameras for preliminary photographic work. Presently, many of the components of the equipment are antiquated or inadequate for the level of complexity of the experiments. This situation can be corrected by the replacement of the computers that control two diffractometers with a single microVAX II, refurbishing of the goniometers of these instruments, replacement of the x-ray generator for the third diffractometer with an ultra-stable solid state generator, construction of a highly stable low temperature device for high resolution work, purchase of a generator and two cameras for photographic work and of a reduced temperature device and V-shaped film cassettes for protein data collection.